Method of dyeing



Patented Apr. 8, 1941 METHOD OF DYEING Winfield Walter Heckert, Ardentown, Del., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application Februar 's, 1938,

Serial No. 188,931

1 Claim.

This invention relates to the coloring of mixed textile materials consisting of textile material comprising an organic derivative of cellulose textile material and textile material of different chemical constitution, and it especially relates to the coloring of mixed textile fabrics wherein the textile material comprising an organic derivative of cellulose has previously been modified in dyeing characteristics by means of a polymeric compound containing in its structureamino nitrogen. Such polymeric compounds are described in Heckert application, Serial No. 143,829 Patent No. 2,191,887, of which the present appliaction is a, continuation-in-part.

Yarns and fabrics of organic derivatives of cellulose, especially of cellulose esters, such as cellulose acetate, are generally non=receptive to acid dyestuffs which are commonly used to dye woolen fabrics. The same is also true of direct dyestuffs which are commonlyused to dye cottonor regenerated cellulose fabrics as well as a great many other dyestuffs commonly employed to dye woolen, silk, cotton or regenerated cellulose goods. Vice versa, the dyestuffs specially developed for use on cellulose acetate materials have relatively little dyeing affinity for woolen, silk,-cotton or regenerated cellulose goods. Commercially, ad-

vantage of this selectivity in dyeing properties has been taken to produce cross dyeing effects since one or theother of the mixed fibers is left undyed and may later be colored with an appropriate dyestufi'. The selectivity in dyeing properties, however, is a disadvantage when it is desired to colonall component fibers in a mixed fabric containing cellulose acetate, and becomes ,7

markedly so when it is desired to dye the mixed fabric to a uniform solid color. In such cases, it is necessary to employ relatively time-consuming I and expensive procedures, for instance in one of the present commercial procedures for dyeing a cellulose acetate containing mixed fabric a solid uniform color, the mixed fabric is dyed with a bath containing a. dyestufi for the cellulose acetate, and then is withdrawn and dyed in a bath containing a dyestuff for the other yarn component in the fabric, each dye being carefully selected so as to dye one type of fiber and not the other.

One object of the instant invention is, therefore, to simplify and render less expensive the dyeing of mixed textile fabrics consisting of organic cellulose derivative yarns and wool, silk, cotton, or regenerated cellulose yarns.

Another object of the invention is to produce a uniformly solid colored mixed textile fabric coni taining wool, silk, cotton, or regenerated cellulose yarns and organic cellulose derivative yarns with a dye having an amnity for W001, silk, cotton, or

regenerated cellulose yarn, but substantially no affinity for unmodified organic cellulose derivative yarn.

A further object of the invention is to uniformly and solidly color throughout mixed textile fabrics containing cellulose acetate yarns by meansof a dye bath containing only a dye or dyes having no afiinity for unmodified cellulose acetate.

' for the wool, silk, cotton, or regenerated cellulose as alpha-methacrylic.

fibers but substantially none for'unmodified cellulose acetate.

In accordance with the preferred manner of carrying out the invention, the following steps may be taken. Cellulose acetate yarns are spun under such conditions that the spun yarns contain by weight 3 to 15% of a polymeric compound containing amino nitrogen, such as a polymerized amino alcohol ester of an acrylic acid such The modified cellulose acetate yarns are woven with wool, silk, cotton, or regenerated cellulose yarns into a mixed textile fabric and the mixed fabric is entered in a dye bath containing a dyestuff or dyestuffs having no affinity for unmodified cellulose acetate, but possessing afiinity for the other fiber in the mixed fabric. The concentration, of the dye bath and time of immersion of the fabric therein are so regulated that the entire mixed fabric, including the modified cellulose acetate yarn, is dyed to a uniform level solid color.

A few examples will now be cited in order to facilitate comprehension of the operation of the inventlon. It will be understood the examples are illustrative only, and are not to be considered limitative.

EXAMPLE I.-(One bath, one temperature, neutralized midway) Polymerized beta-diethylaminoethyl a1 phamethacrylate, prepared as described in Example temperature, and pH- B of Heckert application Serial No. 143,829 is dissolved in acetone and to this solutionsufiicient cellulose acetate is added to form a spinning solution containing 20% cellulose acetate, 2% polymer, and 78% acetone. The solution is dry spun into fibers which are fabricated by standard methods into a crepe fabric, the warp of which consists of modified cellulose acetate fibers and the filling of regenerated cellulose threads. The resulting fabric is submitted to an aqueous scouring bath and entered cold into a dye bath having a 40:1 ratio of liquor volume to fabric weight and containing 2% of a green direct cotton dyestuif of Color Index No. 594, 20% Glaubers salt, and 2.5% acetic acid. With frequent turning of the fabric, the temperature of the dye bath is raised quickly to about 85 C. and held there for twenty minutes after which soda ash is added to neutralize the acidity of the dye bath. After neutralization, the fabric is dyed in the bath at about 85 C. for another 20 minutes with frequent turning, and then is withdrawn, rinsed, and dried. Viewed in piece, the mixed fabric is found to be dyed throughout a uniform level solid green.

Instead of neutralizing the dye bath, one may somewhat less desirably use two dye baths, the first containing 20% Glaubers salt, 2.5% acetic acid, and. 1.2% of the green direct cotton dyestuif and the second being neutral and containing 0. and maintained at that temperature for 30 to 40 minutes while frequently turning the fabric. The mixed fabric is then removed from the dye bath, rinsed well, and entered into a diazotizing 20% Glaubers salt and .8% of the green direct cotton dyestuff. In such case, the mixed fabric is kept in the first bath at about 85 C. until substantially all the dyestuff is exhausted, after the mixed fabric is withdrawn, rinsed, and entered in the second bath which is quickly raised to a temperature of about 85 C. The fabric is frequently turned and after dyeing for about. 20 minutes at a temperature of about 85 C. is withdrawn from the substantially exhausted dye bath, rinsed, and dried.

EXAMPLE II.(Bu17ered, one dye and bath) A crepe fabric, consisting of a warp of cellulose 4 acetate yarns containing 10% polymerized betadiethylaminoethyl alpha-methacrylate, and a fill- 45 fabric piece. The crepe regenerated cellulosemodified cellulose acetate fabric piece is then removed from the dye bath, rinsed and dried. The fabric piece is dyed a uniform level solid red.

EXAMPLE III.(NH4C'2H3O2, 'uiscose rayon-acetate-dzazo) Cellulose acetate yarns containing 10% of polymerized beta-diethylaminoethyl alpha-methacrylate, are incorporated as warp of a crepe fabric in which the filling consists of regenerated cellulose threads. After treatment with the usual aqueous scouring bath, the mixed fabric is entered at about 50 C. in a dye bath having a 40:1

ratio of liquor volume to fabric weight and containing 2% of a blue developable dye of Color Index No. 317, 5% of sodium chloride, and 8% of neutral ammonium acetate. The temperature of the dye bath is next quickly raised to about 85 bath at a temperature of 18-24 C. and containing 3% sodium nitrite and 4% sulfuric acid. After a diazotizing treatment of 20 minutes with occasional turning, the mixed fabric is quickly but thoroughly washed with water and introduced into a developing bath containing 1% beta naphthol as a developer and .5% sodium hydroxide. After treatment with the developing bath for a period of 20 minutes, the mixed fabric is rinsed thoroughly, squeezed out, and dried. The

mixed fabric piece is dyed throughout a uniform level solid blue.

EXAMPLE IV.(Cotton-dne dye) Cellulose acetate staple fibres, containing 5% of polymerized beta-diethylaminoethyl alphamethacrylate, are mixed with cotton, and after being duly processed into a sliver and thread, are woven into a fabric consisting approximately of 50% modified cellulose acetate and 50% cotton.

After the customary aqueous scouring boil-off,.

the mixed fabric is entered at 50-60 C. in a dye bath containing 1% of a red direct cotton dyestufi of Color Index No. 278, acetic acid, and 15% Glaubers salt. The temperature of the dye bath is raised during the course of 15 minutes to C. and the dyeing is continued at this temperature for 45 minutes with frequent turning of the mixed fabric. The cotton-cellulose acetate fabric piece is then removed, and after rinsing and drying is found to be dyed a uniform level solid-red.

EXAMPLE V.(C'0tton-developed dye) EXAMPLE VI.(Wool- 1 cid dye) Cellulose acetate staple fibres, containing 5% of polymerized beta-diethylaminoethyl alphamethacrylate, are mixed with wool fibres and the mixture converted by standard textile operations into a fabric consisting of 50% wool and. 50% modified cellulose acetate. After an aqueous scouring treatment, the wool-cellulose acetate fabric is entered cold in adye bath containing 1% of a red wool acid dye of Color Index No. 430,

15% Glauber's salt, 5% monosodium phosphate,

and 13% disodium phosphate. The dye bath has a pH of about 6.7 and a ratio of liquor volume to weight of fabric of 40:1. The temperature of the dye bath is brought to 85-90" C. within 15 minutes, and the dyeing is continued at that temperature for a period of 45 minutes with frequent turning of the piece goods. The wool modifled cellulose acetate piece goods is then removed from the dye bath, and after rinsing and drying, yields a piece fabric which is dyed a uniform level solid red color.

EXAMPLE VII.-(WooI-chrome dyei Cellulose acetate staple, containing. 5% of polymerized beta-diethylaminoethyl alpha-methacrylate, is mixed with wool and converted by standard procedures into a fabric containing 50% modified cellulose acetate and 50% wool. The mixed fabric after an aqueous scouring treatment is entered cold in a dye bath having a ratio of liquor volume to weight of fabric of 40: 1 and containing 1% of a chrome dye (Anthracene Chromate Brown EB-Prototype No. 12), 15% of Glaubers salt and .1% of acetic acid. After turning the fabric frequently in the cold bath for minutes, the temperature of the dye bath is raised to 85-90 C. in the space of minutes and is held at that temperature for 45 minutes while the fabric is frequently turned. At the end of the 45 minutes, the fabric is lifted and 1% of chromic acid and 2% of acetic acid, dissolved in a small amount of cold water, are added to the dye bath. Once more the fabric is submerged in the dye bath and the temperature of the bath is raised slowly to 85-90 C. and maintained there for 30 minutes while the fabric is frequently turned. The wool-modified cellulose acetate fabric -is withdrawn, rinsed, and dried. The finished fabric piece is dyed a uniform level brown color.

EXAMPLE VIII.(Sz'lk-direct dye) A piece of velvet goods having a backing of natural silk and a pile facing of cellulose acetate yarns containing 10% of polymerized beta-diethylaminoethyl alpha-methacrylate is first submitted to the usual scouring treatment and then is entered at 50 C. into a. dye bath having a ratio of liquor volume to fabric weight of 40:1 and containing 2% of a blue direct cotton dyestufi of Color Index No. 512, and 20% of Glaubers salt. The temperature of the dye bath is raised to 85 C. in the space of 15 minutes after which 5% of acetic acid is added. After 15 minutes at 85 C. and frequent turning of the velvet fabric, an additional 5% of acetic acid is added to the nearly exhausted dye bath and the dyeing continued for another 15 minutes. After removal from the dye bath, rinsing, and drying, the velvet exhibits a very satisfactory blue union between the silk backing and the modified cellulose acetate pile facing.

EXAMPLE IX.(SiZk-acid dye) dye bath is brought to 85 C. in the space of 15 minutes and dyeing continued at that temperature for 30 minutes while frequently turning the velvet goods. The velvet goods is then lifted, 1% of sulfuric acid is added, and the dyeing completed during the'space of about 15 minutes while 1 turning frequently the velvet fabric. After withdrawal, rinsing, and drying, a velvet fabric is secured showing a pleasing blue union between backing and pile facing.

EXAMPLE X A mixed fabric consisting of a warp of cellulose acetate yarns containing 10% polymerized betadiethylaminoethyl alpha-methacrylate, and a acid. After 5 minutes at room temperature the Y weft of regenerated cellulose threads, is dyed with a green vat dyestuif paste of Color Index No. 1101 in the following manner:

Twenty parts of the dye paste are mixed with parts of the following composition:

550 parts of a boiled mixture comprising 700 parts gum tragacanth (6%) and 300 parts British gum powder 190 parts potassium carbonate .Dis'solve at 75 0., cool to. 60 C. and add:

160 parts sodium formaldehyde sulfoxylate 50 parts glycerin 50 parts water.

Parts Sodium perborate 5 Water 1000 After oxidation, the printed mixed fabric is rinsed, soa ped lightly, rinsed, and dried. If desired, the mixed fabric may first be dyed with a developed dye of a Color Index No. 317 and the r fabric printed in the above fashion to secure a colored printed pattern on a differently colored background.

EXAMPLE In A mixed fabric, consisting of a warp of cellulose acetate yarns containing 10% of polymerized beta-diethylaminoethyl alpha-methacrylate, and a weft of regenerated cellulose yarns is dyed a blue color by the procedure of Example III with the blue developable dyestuff of Color Index No. 317. A white printed pattern on the blue backthe dyed mixed fabric, dried, aged for 4 to 6 minutes at IOU- C. in an air-free ager,rinsed, soaped, rinsed, and dried.

In all the above examples, unless otherwise specified, percentages are based on the'weight of the mixed material being treated.

The process of the invention, consisting of modifying the cellulose acetate, producing a mixed material from the modified cellulose acetate and another fibre, and union dyeing the mixed material with a dyestuif having normally an aflinity for the other thread but none for the cellulose acetate, is applied particularly advantageously to the production of solid colored effect on cellulose acetate mixed textile materials. However,

it will be appreciated by the skilled technician that the process of the invention may also be applied with suitable variations broadly to union dyeing of mixed textile materials whenever it is desired that the cellulose acetate be definitely colored by the dyestuif selected for dyeing the other component fibre and having normally no aflinity for cellulose acetate. Thus, by suitable variations of such factors as the temperature of the dye bath, the amount of modifier incorporated in the cellulose acetate, and the pH of the dye bath, the modified cellulose acetate fibre and the other component fibre or fibres of the mixed fabric may readily be colored to different depths to produce a pleasing colored cross dyeing effect in a single dye bath, notwithstanding that the dyestufi selected has no afi'i'nity for unmodified cellulose acetate,

While in the above examples, polymerized betadiethylaminoethyl alpha-methacrylate has been used as the modifier, the process of the invention may be accomplished satisfactorily by the use of any other non-cellulosic, non-proteinous polymeric compound containing amino nitrogen, particularly an acetone soluble resinous one containing at least 2% amino nitrogen and soluble in 2% aqueous acetic acid but insoluble in water and 5% aqueous ammonia. Especially preferred as modifiers are the polymerized amino alcohol esters of arcylic acid containing a basic tertiary amino nitrogen group, such as beta-diethylaminoethyl alpha-methacrylate, beta-dimethylaminoethyl alpha-methacrylate, beta-piperidyl-N- ethyl-alpha-methacrylate, and beta-dicyclohexylaminoethyl alpha-methacrylate. As other suitable polymeric compounds containing amino nitrogen may be mentioned, non-cellulosic hexose amine polymer, such as deacetylated chitin; synthetic-resins such as reaction products of phenol with aldehyde and ammonia or amines and resinous condensation polymers of aminodihydric alcohols with dibasic acids such as diethanolmethlyamine succinate and diethanolmethylamine phthalate. As examples of the phenolaldehyde-amine type resin may further be mentioned the reaction products between phenol, formaldehyde, ammonia,- and dimethylamine; between phenol, lignin, formaldehyde, and dimethylamine; between phenol, formaldehyde, and dimethylaminoethanol; between phenol, formaldehyde, and dimethylol cyclohexanolamine; between phenol, formaldehyde, ammonia, and

' aniline; and many others. Instead of simple polymers, interpolymers may be used, for instance, a reaction product of methylmethacrylate with methyl vinyl ketone in the presence of ammonium hydroxide or the reaction product of beta-cyclohexylaminoethyl methacrylate monomer with beta-dimethylaminoethyl methacrylate monomer under suitable conditions.

Preferably the modifier is incorporated in the spinning solution but it may also be incorporated in any other suitable manner in the cellulose acetate materials; for instance, the polymeric modifier may be dispersed in a suitable solvent or dispersing medium, thecellulose acetate material impregnated with the solution or dispersion, and the solvent or dispersing medium removed. In some cases, it may be desirable to incorporate the resin-forming components or monomer in the cellulose acetate structure and to. form the resin in situ.

If the polymer is to be added to the spinning solutions, concentrations as high as 30% or even more, based on the weight of cellulose acetate, may be used. In general, however, concentrations ranging from about 3% up to about 15% or more are sufiicient for most purposes. While it is possible to increase the depth of dyeing by larger quantities of the polymeric modifier, the increased dyeing depth is offset by weakening of the cellulose acetate structure.

The invention may be employed to secure colored effects throughout a mixed material, containing modified cellulose acetate, with most any dyestufi having little, if any, affinity for unmodified cellulose acetate; the only requisite is that the selected dyestufi have a natural affinity for the other thread component of the mixed material. Of the many classes and individual dyestufis which have proven suitable may be mentioned as typical:

Direct dyes Pontamine Scarlet B Color Index 382 Pontamine Blue RWG Color Index 512 Also the direct dyes having the Color Index numbers 326, 533, 594, 415, 278, and 581.

Acid dyes Milling Red R Color Index 430 Anthraquinone Blue Sky Color Index 1088 Also acid dyes having Color Index numbers 667, 307, and 31.

Developed color dyes (dzazo dyes) Pontamine maze Black 12s---- Color Index 552 Pontamine Diazo Blue NA Color Index 317 Also developed dyes having Color Index numbers 401, 324a, and 1934 Yearbook Prototype 62.

Chrome dyes Pontacyl Rubine R--- Color Index 179 Chromate Brown EB 1934 Yearbook Prototype 12 Also chrome dyes having Color Index numbers 216, 40, and 299.

All Color Index numbers appearing in the present specification are those given in the 1934 Yearbook of the American Association of Textile Chemists and Colorists.

It will be understood the dyeing conditions given in the above examples may be varied somewhat provided other factors are correspondingly adjusted. Likewise, in many cases, the dyeing conditions will have to be adjusted according to the characteristics of the particular dyestufi selected, the type of color effect desired, and the particular threads combined with the modified cellulose acetate in the mixed material. However, it is believed all such adjustments may be readily performed by following the principles outlined in the present invention. Generally speaking, the adjustments may be accomplished by suitable variation of all or part of the following factors: the amount of polymeric modifier incorporated in the cellulose acetate, the concentration of the dyestufi in the dye bath, the temperature of the dye bath, and the acidity or pH of the dye bath. Thus, for example, if a solid colored union is desired, and the modified cellulose acetate is being dyed too lightly, the condition may frequently be corrected by increasing the amount of polymeric amino containing modifier in the cellulose acetate. Again in certain cases such as where the other component of the mixed fabric is wool or silk, the differences may be eradicated by dyeing initially at an elevated temperature for a suitable period and then finishing the dyeing at a lower temperature, or vice versa dyeing initially at a lower temperature and finishing at an elevated temperature.

Most of the necessary dyeing control, however, is preferably attained through regulation of the acidity or pH of the dye bath. As pointed out in the above examples, such regulation may either be accomplished by changing the acidity by posit.ve addition of suitable acidic or basic reagents during the union dyeing operation or by the use of a properly buffered dye bath. Generally speaking, it is essential in making the union dyed materials of the invention that at some stage in the dyeing the dye bath be somewhat acidic, for instance, of a pH between 6.9 and 5 and preferably between 6 and 5. In the case where the acidity is controlled by buffering the dye bath, most any of the buffering combinations or acid salts of phosphoric, boric, sulfuric, citric, carbonic, tartaric, or the like may be used to advantage. In cases wherein a progressive increase in acidity of the dye bath is desired, it is preferred to employ ammonium salts such as ammonium acetate or ammonium sulfate. Customary wetting agents used'in dyeing operations may be present in the dye bath if desired.

It will be understood that the process of the invention may be applied advantageously to the dyeing in one bath of a mixed fabric of cellulose acetate and another material with a dyestufi having normally afi'inity only for the second mate rial regardless of the physical form of the mixed materials. Thus, the modified cellulose acetate and the second material may be in the form of staple, fibres, threads, yarns, straws, ribbons, skeins, rovings, slivers, or woven and knitted fabrics such as suitings, crepes, velvets, hosiery, and car upholstery. Likewise, the modified cellulose acetate may be mixed with only one or with two or more materials depending as to whether a solid colored union is desired and in such case whether the materials added to the modified cellulose acetate can be dyed to substantially the same shade and color. With certain dyestuffs, the shade or color tone of the dye on the modified cellulose acetate component is somewhat different from that on the other component or components of the mixed material. Such is sumcientLv satisfactory in many cases; if, however, a solid colored union of exactly matched shade and color tone is desired, it is possible to accomplish the same by addition of a proper auxiliary dyestufi having a natural aflinity for the other component or components of the mixed material but none for unmodified cellulose acetate.

In discharge printing, where it is desired to secure a white pattern effect on a colored background, as well as in cases where the color is to be stripped substantially completely from the union dyed fabric, the zinc formaldehyde sulfoxylate, sodium formaldehyde sulfoxylate, or other discharge agent may be applied successfully either in the presence or absence of a swelling agent, such as zinc thiocyanate.

For convenience, the invention has been discussed in terms of cellulose acetate. The invention, however, is applicable also to other organic esters of cellulose, for instance, cellulose acetopropionate, cellulose acetostearate, and cellulose propionate as well as cellulose ethers, such as methyl, ethyl, glycol, or benzyl cellulose in the same manner as above described with reference to the cellulose acetate.

Obviously, the cellulose acetate to be modified and the mixed fabric dyed by the process of the invention may, if desired, contain besides the dye modifier, titanium dioxide or other inorganic and organic pigments as well as plasticizers, waxes, and similar substances.

Prior to the present invention, green and black solid unions were especially difficult to obtain. In contrast the process of the instant invention offers a relatively simple and inexpensive procedure of union dyeing cellulose acetate containing fabrics in essentially one dye bath by'means of a dyestufl which has no aflinity for. unmodified cellulose acetate. By such means new beautiful solid colored unions in cellulose acetate mixed materials may be secured over a wide range of colors and shades including greens and blacks and in the most delicate and brilliant hues. A subsidiary advantage of the invention is the substantially complete exhaustion of the dyestuffs from the dye bath.

Many changes'and modifications of the specific details hereinabove described can be made without departing from the nature and spirit of the invention, and it is, therefore, to be understood that the invention is not to be limited except as set forth in the appended claim. A

I claim: a

The process of dyeing a mixed textile structure composed of cellulose acetate and a material other than cellulose acetate with a dyestuff having an afiinity for said other material but having substantially no aflinity for said cellulose acetate material which comprises modifying said cellulose acetate material by the incorporation therein of a polymerized beta-diethylaminoethyl alpha-methacrylate whereby to impart thereto an afiinity for said dyestufi, forming said mixed textile structure with said modified cellulose acetate material, and dyeing said structure with said dyestufi.

WINFIELD WALTER HECKERT.

CERTIFICATE .OF CORRECTION. Patent No. 2,257,829. April 19in.

WINFIELD WALTER HECKERT.-

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, line 55, for "after the" read after which the--; page 1 first column, line 1h, for cylic" read -scrylic-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office. 7 Y

Signed and sealed this 15th day of May, A. D. 19in.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

